TimeStamp type uses incorrect endianness?

[stefano-pogliani]

Hello,

I have recently attempted to use the new bson::TimeStamp type to decode an optime returned by the replSetGetStatus MongoDB command.
The value that I got was different from the result of rs.status().

After a bit of investigation I noticed the timestamp is converted to big endian before it is masked and shifted: https://github.com/zonyitoo/bson-rs/blob/master/src/decoder/serde.rs#L595

I am not familiar with the protocol but other clients (including the bson package in the mongodb repo) seem to use little endian encoding for the values of the timestamp:

• Go Client: https://github.com/mongodb/mongo-go-driver/blob/master/bson/value.go#L820
• Comment in the official MongoDB codebase: https://github.com/mongodb/mongo/blob/master/src/mongo/bson/timestamp.cpp#L51-L52

Is this indeed a bug or am I doing something wrong?

[saghm]

This looks like a bug to me; the BSON spec indicates that the value of a Timestamp is the "basic type" uint64, which is described as little endian: http://bsonspec.org/spec.html

[stefano-pogliani]

Unrelated to this behaviour I also have a commit to implement serde Serialise on the new bson::TimeStamp that I would like to submit for consideration.

Should that be a separate PR?

[zonyitoo]

That must be a bug. Thanks for your contribution.

[zonyitoo]

@stefano-pogliani Implement Serialize for bson::TimeStamp separately? How? You should open a PR if you want to.